scholarly journals The evidence for anthocyanins in the betalain-pigmented genus Hylocereus is weak

2021 ◽  
Author(s):  
Boas Pucker ◽  
Samuel F. Brockington

Here we respond to Zhou et al., 2020 'Combined Transcriptome and Metabolome analysis of Pitaya fruit unveiled the mechanisms underlying Peel and pulp color formation' published in BMC Genomics. Given the evolutionary conserved anthocyanin biosynthesis pathway in betalain-pigmented species, we are open to the idea that species with both anthocyanins and betalains might exist. However, in absence of LC-MS/MS spectra, apparent lack of biological replicates, and no comparison to authentic standards, the findings of Zhou et al., 2020 are not a strong basis to propose the presence of anthocyanins in betalain-pigmented pitaya. In addition, our re-analysis of the datasets indicates the misidentification of important genes and the omission of key anthocyanin synthesis genes ANS and DFR. Finally, our re-analysis of the RNA-Seq dataset reveals no correlation between anthocyanin biosynthesis gene expression and pigment status.

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiqing Peng ◽  
Xujie Dong ◽  
Chao Xue ◽  
Zhiming Liu ◽  
Fuxiang Cao

Hydrangea macrophylla has a large inflorescence and rich colors, which has made it one of the most popular ornamental flowers worldwide. Thus far, the molecular mechanism of flower color formation in H. macrophylla flowers is unknown. By comparing the pigment content and transcriptome data of the bud period (FSF1), discoloration period (FSF2) and full-bloom stage (FSF3) of infertile blue flowers of H. macrophylla cv. “Forever Summer,” we found that genes associated with anthocyanin production were most associated with the formation of blue infertile flowers throughout development. The anthocyanin biosynthesis pathway is the main metabolic pathway associated with flower color formation, and the carotenoid biosynthesis pathway appeared to have almost no contribution to flower color. There was no competition between the flavonoid and flavonol and anthocyanin biosynthesis pathways for their substrate. At FSF1, the key genes CHS and CHI in the flavonoid biosynthesis pathway were up-regulated, underlying the accumulation of a substrate for anthocyanin synthesis. By FSF3, the downstream genes F3H, C3′5′H, CYP75B1, DFR, and ANS in the anthocyanin biosynthesis pathway were almost all up-regulated, likely promoting the synthesis and accumulation of anthocyanins and inducing the color change of infertile flowers. By analyzing protein–protein interaction networks and co-expression of transcription factors as well as differentially expressed structural genes related to anthocyanin synthesis, we identified negatively regulated transcription factors such as WER-like, MYB114, and WDR68. Their site of action may be the key gene DFR in the anthocyanin biosynthesis pathway. The potential regulatory mechanism of flower color formation may be that WER-like, MYB114, and WDR68 inhibit or promote the synthesis of anthocyanins by negatively regulating the expression of DFR. These results provide an important basis for studying the infertile flower color formation mechanism in H. macrophylla and the development of new cultivars with other colors.


2018 ◽  
Author(s):  
Xi Ou Xiao ◽  
Wen qiu Lin ◽  
Ke Li ◽  
Xue Feng Feng ◽  
Hui Jin ◽  
...  

We obtained a white-peel eggplant (L6-5) by EMS mutation in our previous study, whose total anthocyanin content was significantly decreased as compared with that of wild-type (WT). To analyse the anthocyanin biosynthesis mechanism in eggplants, we analysed the eggplant peel by RNA-seq in this study. The transcript results revealed upregulation of 465 genes and downregulation of 525 genes in L6-5 as compared with the WT eggplant. A total of 11 anthocyanin biosynthesis structure genes were significantly downregulated in L6-5 as compared with that in WT. Meanwhile, on the basis of the RT-PCR results of four natural eggplant cultivars, the expression pattern of 11 anthocyanin biosynthesis structure genes was consistent with the anthocyanin content. Thus, we speculated the anthocyanin biosynthesis pathway in eggplant peel. The transcript and RT-PCR results suggested positive regulation of MYB1, MYB108 and TTG8 and negative regulation of bHLH36 in anthocyanin biosynthesis. This study enhanced our cumulative knowledge about anthocyanin biosynthesis in eggplant peels.


2011 ◽  
Vol 322 (2) ◽  
pp. 145-149 ◽  
Author(s):  
Jiujiang Yu ◽  
Natalie D. Fedorova ◽  
Beverly G. Montalbano ◽  
Deepak Bhatnagar ◽  
Thomas E. Cleveland ◽  
...  

2003 ◽  
Vol 160 (8) ◽  
pp. 971-975 ◽  
Author(s):  
Maha Afifi ◽  
Ashraf El-Kereamy ◽  
Valérie Legrand ◽  
Christian Chervin ◽  
Marie-Carmen Monje ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaojuan Yin ◽  
Yibing Zhang ◽  
Li Zhang ◽  
Baohua Wang ◽  
Yidi Zhao ◽  
...  

Flower color is the decisive factor that affects the commercial value of ornamental flowers. Therefore, it is important to study the regulation of flower color formation in lily to discover the positive and negative factors that regulate this important trait. In this study, MYB transcription factors (TFs) were characterized to understand the regulatory mechanism of anthocyanin biosynthesis in lily. Two R2R3-MYB TFs, LvMYB5, and LvMYB1, were found to regulate anthocyanin biosynthesis in lily flowers. LvMYB5, which has an activation motif, belongs to the SG6 MYB protein subgroup of Arabidopsis thaliana. Transient expression of LvMYB5 indicated that LvMYB5 can promote coloration in Nicotiana benthamiana leaves, and that expression of LvMYB5 increases the expression levels of NbCHS, NbDFR, and NbANS. VIGS experiments in lily petals showed that the accumulation of anthocyanins was reduced when LvMYB5 was silenced. Luciferase assays showed that LvMYB5 can promote anthocyanin synthesis by activating the ANS gene promoter. Therefore, LvMYB5 plays an important role in flower coloration in lily. In addition, the transient expression experiment provided preliminary evidence that LvMYB1 (an R2R3-MYB TF) inhibits anthocyanin synthesis in lily flowers. The discovery of activating and inhibitory factors related to anthocyanin biosynthesis in lily provides a theoretical basis for improving flower color through genetic engineering. The results of our study provide a new direction for the further study of the mechanisms of flower color formation in lilies.


2019 ◽  
Author(s):  
Jian Gao ◽  
Mao Luo ◽  
Yi Liu ◽  
Fabo Chen ◽  
Hua Peng ◽  
...  

Abstract Radish ( Raphanus sativus L.), belonging to biennial root vegetable crop of Brassicaceae family, is an economically important vegetable crop with an edible taproot. Recently, most of differential expressed genes associating with anthocyanin biosynthesis have been identified in most of important fruit crops. However, transcriptome analysis of anthocyanin biosynthesis and expression of anthocyanin biosynthesis related genes in ‘Hongxin’ radish have not been fully investigated. Here, based on results from HPLC analysis, young fleshy roots obtained from the dynamics development stage of fleshy roots in carmine radish ‘Hongxin 1’ was used for RNA-Seq, including fleshy roots from seedling stage (SS), initial expansion (IE), full-expansion (FE), bolting stage (BS), initial flowering stage (IFS); full-bloom stage (FBS) and podding stage (PS). Subsequently, the putative candidate genes involved in the dynamics development stage of fleshy roots in carmine radish were identified. After that, DGE (differential gene expression) profile analysis was used to identify the pupative transcripts, compared with fleshy roots from seedling stage (SS). In addition, co-modulated DEGs (Common DEGs in the dynamic growing stages of fleshyroot in carmine radish) were also identified, from which most DGEs were more likely to participate in anthocyanin biosynthesis, including two transcription factors RsMYB and Rs RZFP . In addition, some related proteins e.g. RsCHS , RsDFR , RsANS , RsF’3H , RsF3GGT1 , Rs3AT1 , glutathione S-transferase F12, RsUFGT78D2-like and RsUDGT-75C1-like were significantly contributed to the regulatory mechanism during anthocyanin synthesis in the development stage of fleshy roots. Furthermore, GO terms comprised of “anthocyanin-containing compound biosynthetic process” and “anthocyanin-containing compound metabolic process” were commonly overrepresented in the other dynamics growing stages of fleshy roots after initial expansion of fleshy roots. Moreover, these results indicated that five significantly enrichment pathways of DEG were identified for the dynamics growing stages of fleshy roots in carmine radish, including Flavonoid biosynthesis, Flavone and flavonol biosynthesis, Diterpenoid biosynthesis, Anthocyanin biosynthesis, as well as Benzoxazinoid biosynthesis. These results will expand our understanding of complex molecular mechanism of the putative candidate genes involved in the dynamics development stage of fleshyroot in carmine radish.


BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhaoxi Zhou ◽  
Hongmao Gao ◽  
Jianhong Ming ◽  
Zheli Ding ◽  
Xing’e Lin ◽  
...  

Abstract Background Elucidating the candidate genes and key metabolites responsible for pulp and peel coloration is essential for breeding pitaya fruit with new and improved appeal and high nutritional value. Here, we used transcriptome (RNA-Seq) and metabolome analysis (UPLC-MS/MS) to identify structural and regulatory genes and key metabolites associated with peel and pulp colors in three pitaya fruit types belonging to two different Hylocereus species. Result Our combined transcriptome and metabolome analyses suggest that the main strategy for obtaining red color is to increase tyrosine content for downstream steps in the betalain pathway. The upregulation of CYP76ADs is proposed as the color-breaking step leading to red or colorless pulp under the regulation by WRKY44 transcription factor. Supported by the differential accumulation of anthocyanin metabolites in red pulped pitaya fruit, our results showed the regulation of anthocyanin biosynthesis pathway in addition to betalain biosynthesis. However, no color-breaking step for the development of anthocyanins in red pulp was observed and no biosynthesis of anthocyanins in white pulp was found. Together, we propose that red pitaya pulp color is under the strict regulation of CYP76ADs by WRKYs and the anthocyanin coexistence with betalains is unneglectable. We ruled out the possibility of yellow peel color formation due to anthocyanins because of no differential regulation of chalcone synthase genes between yellow and green and no detection of naringenin chalcone in the metabolome. Similarly, the no differential regulation of key genes in the carotenoid pathway controlling yellow pigments proposed that the carotenoid pathway is not involved in yellow peel color formation. Conclusions Together, our results propose several candidate genes and metabolites controlling a single horticultural attribute i.e. color formation for further functional characterization. This study presents useful genomic resources and information for breeding pitaya fruit with commercially attractive peel and pulp colors. These findings will greatly complement the existing knowledge on the biosynthesis of natural pigments for their applications in food and health industry.


BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xinkang Feng ◽  
Gang Gao ◽  
Chunming Yu ◽  
Aiguo Zhu ◽  
Jikang Chen ◽  
...  

Abstract Background The bast fiber crop ramie can be used as high-quality forage resources, especially in tropical or subtropical region where there is lack of high-quality protein feed. Hongxuan No.1 (HX_1) is a unique ramie variety with a light reddish brown leaf color, which is obviously different from elite cultivar, Zhongzhu No.1 (ZZ_1, green leaf). While, the regulatory mechanism of color difference or secondary metaboliates synthesis between these two varieties have not been studied. Results In this study, phenotypic, transcriptomic and metabolomic analysis of HX_1 and ZZ_1 were conducted to elucidate the mechanism of leaf color formation. Chromaticity value and pigment content measuring showed that anthocyanin was the main metabolites imparting the different leaf color phenotype between the two varieties. Based on LC/MS, at least 14 anthocyanins were identified in leaves of HX_1 and ZZ_1, and the HX_1 showed the higher relative content of malvidin-, pelargonidin-,and cyanidin-based anthocyanins. Transcriptome and metabolome co-analysis revealed that the up-regulated expression of flavonoids synthesis gene was positively correlated with total anthocyanins accumulation in ramie leaf, and the differentfially expression of “blue gene” (F3’5’H) and the “red gene” (F3’H) in leaves bring out HX_1 metabolic flow more input into the cyanidin branch. Furthermore, the enrichment of glycosylated modification pathway (UGT and AT) and the expression of flavonoid 3-O-glucosyl transferase (UFGT), anthocyanidin reductase (ANR), in leaves were significantly influenced the diversity of anthocyanins between HX_1 and ZZ_1. Conclusions Phenotypic, transcriptomic and metabolomic analysis of HX_1 and ZZ_1 indicated that the expression levels of genes related to anthocyanin metabolism contribute to the color formation of ramie variety. Anthocyanins are important plant secandary metabilates with many physiological functions, the results of this study will deepened our understanding of ramie leaf color formation, and provided basis for molecular breeding of functional forage ramie.


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